The present invention relates to a vessel, particularly to a vessel having walls of a material which permits heating of the content of the vesssel by radiation, in particular micro-wave radiation.
Such vessels, and the term vessel is used here to include also packages and containers of different kinds which normally, at least partially, have walls of a material which depends on the actual kind of heating. If the heating takes place by heat radiation of the type infrared heat radiation from e.g. a cooking plate, the material may be metal, at least in the bottom. If the heating takes places by means of the nowadays very common heating type using micro-vawes, then the material may be cardboard or plastics or the like. Below, to facilitate, such vessels, along with the instant content in each case, will sometimes be referred to as "object".
Common to all types of heating is the problem of accurately controlling the temperature, e.g. to prevent that the temperature is insufficient for the application in question or to prevent that the vessel as used bursts up and starts leaking due to too a high internal pressure within the vessel, which may happen if the temperature has unintentionally become too high. This problem has been solved, to essential proportions, by the invention that constitutes the subject matter of the patent . . . (Swedish patent application number 95 01942, filed May 24, 1995).
According to the just mentioned patent a solution of the recited problem has been achieved in that the vessel is provided with an information carrier having one or more optically readable control information fields which information carrier is adapted to be used in order to indicate the temperature of the object as the object is heated in an oven. Here, it is conceivable, for instance, to watch visually how the information carrier shifts color as the desired temperature has been reached, so that the heating procedure may be stopped then.
However, the information carrier is preferably adapted to cooperate with an optical reading device of the oven and a control device to control the heating procedure at least partially in dependence of the read temperature information.
According to the invention it is preferred that the information carrier is arranged directly on the heating object, e.g. as a disposable label or, alternatively, as a device for repeated use, which device is applied on the object, its vessel, package or container, e.g. as the heating is performed.
According to the said patent it is preferred that the label or device comprises a field of temperature sensitive color which exhibits a color shift at the desired end temperature of the object, preferably the ready-temperature of a food-stuff or a beverage.
It is conceivable, according to the invention, that the information carrier has the shape of a label or a device for use in an oven having a lighting within the oven cavity, in which case the information carrier preferably is characterized in that the field with temperature sensitive color is composed of two layers, viz. an uppermost layer, which shifts from transparent into non-transparent, or vice versa, at a color shift, and a lowermost layer, which exhibits fluorescense at activation by the oven cavity lighting.
In the patent it has been stated that the invention generally is based on the concept that it is possible to utilize optical reading for the provision of a control system for an oven, which is partially associated with the oven itself, and the technical establishment thereof, and which is partially associated with the object or the food-stuff which should be subjected to heating/preparation, and, further, the realization that such a system, particularly the case with feed-back control, which in known ovens is solely associated with the technical establishment of the oven, may achieve considerable simplifications in the design of the control system of the oven and the general operation of the oven, and that this may be achieved while utilizing cost efficient technical solutions that are known per se by those skilled in the art. There exists no principal limit for how much control information may be taken from the information carrier. Just as well as the information carrier may hold information for choice of a pre-set program with the control unit of the oven, the information carrier itself may comprise the control program, which is then read into the control unit at the actual use. In the present case the term optical reading is used, e.g. reading while using light vawelengts within the optical range, but also other vawelengths may be possible. Thus, the information carrier may comprise fields with chrystalline or similar substances which at activation by scanning radiation my be cauesd to emit their information by discrete vawelengths or within defined vawelength-ranges. A feedback control may be achieved in that these substances are adapted to emit radiation of a temperature dependent vawelength.
According to a further development of the invention the vessel may be provided with a further characterizing feature in the shape of an additional, temperature non-sensitive color marking which is disposed in such a manner that it can be detected by a further detecting device, adapted to control the start of the heating procedure. Only vessels having a marking that controls the stop of the heating are provided with the additional color marking, which results in that if a vessel that lacks both kinds of markings is inserted into e.g. a microvawe oven having an indicator for stopping of the heating then no heating can be started. In this way it is prevented that a heating is started that cannot be automatically interrupted at the desired temperature.
In view of the fact that many manufacturers are able to provide information cariers and various kinds of color marks which may be useful for the above recited purposes it would be conceivable that vessels provided with information carriers or separate information carriers for application to vessels and intended to function in the above described ways would be produced and sold by unauthorized persons. Of course, this means a serious disadvantage, e.g. in that an authorized manufacture of vessels might be accused and declared guilty for faults and deficiencies of vessels that have been unauthorized manufactured and sold.
The present invention has for its object to remedy the just mentioned disadvantage and to provide a vessel which permits authorized use only.
To the just mentoned end the vssel according to the present invention is characterized essentially in that it is provided with an identification marking which is adapted to cooperate with a detecting means, preferably disposed within the oven, which means is adapted to actuate a control device which permits function of the oven only if one or more pre-determined identification requisites are met.
Preferably, the identification marking comprises one or more holograms which may be designed in comparatively complicated patterns or combinations thereof and thus may be nearly impossible to counterfeit. Further, they may be either visible, in which case they may fullfill decorative purposes, or hidden for the eyes, in which case the security against unauthorized use of vessels of the above recited kind is further enhanced.